Specific Recognition of a Xanthomonas campestris Florida Citrus Nursery Strain by a Monoclonal Antibody Probe in a Microfiltration Enzyme Immunoassay. T. A. Permar, U.S. Department of Agriculture, Agricultural Research Service, Orlando, FL 32803; T. R. Gottwald, U.S. Department of Agriculture, Agricultural Research Service, Orlando, FL 32803. Phytopathology 79:780-783. Accepted for publication 21 February 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1989. DOI: 10.1094/Phyto-79-780.

A monoclonal antibody (MCA), anti-X-4600 MCA, was developed to a Florida citrus nursery strain of Xanthomonas campestris. Application of this MCA in a microfiltration immunosorbent assay showed that at least two serologically distinct populations of the bacteria exist in Florida. A total of 30 strains representing 13 separate disease occurrences were assayed. Of these, 14 isolates from six locations tested positive. The anti-X-4600 MCA did not react with bacteria other than Florida citrus nursery strains. Comparisons were made of purified and unpurified anti-X-4600 MCA in ELISA and microfiltration enzyme immunosorbent assays with heat-treated and Formalin-fixed bacteria. Purity of the anti-X-4600 MCA had no effect on antibody specificity, and the ELISA and the microfiltration assay were not different in sensitivity. Heat treatment of the bacteria, however, did cause a substantial reduction in response to the MCA.